Coffee roaster and method of roasting coffee



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Patented Nov. 5, 1940 UNITED STAITES PATENT OFFICE COFFEE BOASTEB AND METHOD OF ROASTING COFFEE Donald Wl Adams and Richard L. Schuhmann,

Louisville, Ky., asslgnors, by menne assignments, to Coffee Electrost Corporation. a corporation oi Delaware Application Anm: 1s, 1931, serial No. 159,860

6Clalms.

l serial No. 81,890, med May 2s, 1936, and serial No, 151,744, filed July 2, 1937.

.It is highly desirable that, as soon as coffee has reached the desired temperature in the roasting chamber, the roasting should' be inmediately checked or quenched in order to prevent overroasting with the consequentscorching of the coffee which greatly impairs and often completely spoils its davor. In commercial batch roasting, as practiced today, it is necessary to spray the coiee with cold water in order to arrest or check the roasting. However, when the coiee bean is roasted and attains a relatively high temperature, the oils therein are driven to the surface oi the bean by the absorbed heat.

2G When'cold water is sprayed on the bean in this condition, a considerable amount of the free oils, `which give the bean its flavor and aroma, volatili and are carried away with the steam resulting from the cold water coming in contact with 25 the hot bean. This causes a loss of flavor and aroma and shrinking of the bean. Moreover, the pores of the beans are opened by the heat and to chill them too suddenly, as by the application of cold water, results in immediate contraction of 30 these pores which prevents the exuded oils from re-entering the bean with consequent loss of flavor.

The present invention is designed primarily for a relatively small coffee roaster to be used in $5 grocery stores, delicatessens and the like and con- 40 vent over roasting and scorching of the coiee without at the same time causing the oils in the bean to vaporize or the pores of the beans to close thereby preventing the reentry of the oils into the beans, both resulting in loss of davor and aroma.

Our invention comprises a dry quenching chamber and a separate dry cooling chamber. As

soon as the beans in the roasting chamberhave attained a predetermined correct roasting tem- 50 perature, 'the beans are immediately discharged,

by an automatic arrangement disclosed more fully in our pending application Serial No. 81,890, into a dry quenching or first cooling chamber, preferably located directly below the roastin This chamber is preferably larger than theroasting chamber in order to spread the beans in a rthin layer in the bottom thereof and is equipped with impeller means adapted to rapidly and uniformly move the beans in circular gyratory paths or streamsv throughout the chamf ben thereby separating, rolling, spinning and swirling the individual beans in various paths or streams so that the roasted coilee is given a thorough quenching action by the cool air in the chamber. The roasting is effectively checked but there is no sudden drop in the temperature of the beans with the harmful effects noted above.

In the bottom of this chamber is a small opening directly below which is the second coolingl chamber whichis preferably a screened or foraminous container below which is a strong blowing means for sucking a large quantity of cool air through the chamber and the beans therein. As the impeller in the rst chamber ypushes the beans over the bottom of the chamber, a small quantity of beans will trickle through the opening and be spread over the floor of the second chamber where the rush of cool air therethrough will cool them rapidly. Inasmuch as these beans have already been given a quenching action in the ilrst chamber whereby the oils have reentered the beans and the pores closed, the flavor and aroma oi! the beans are not damaged by the rapid cooling in the second chamber. Moreover vaporization of the oils is` eiectively stopped by the rapid cooling and it is of course desirable to cool the beans as rapidly as possible in order to make room for another batch,

We have found thaty this new cooling means and method result in a much quicker cooling action than was heretofore known, and at the same time result in the coiee retaining its full aroma and flavor. This dry quenching and cooling of the roasted coffee has long been recognized .as preferable over water cooling but has not been widely used because o! the danger oi over roasting by the various apparatus heretofore used in the art. The water quenching was very effective to prevent over roasting but was distinctly undesirable because of the loss of flavor explained above. Our invention has resulted in eliminating all the bad, effects oi.' the prior art cooling methods and has resulted in effective cooling of coee without the use of water.

l Further objects are to provide a construction of maximum simplicity, eillciency. economy and ease of assembly and operation, and such further objects. advantages and capabilities as will later more fully appear and are inherently possessed thereby.

The invention further resides in the construction, combination and arrangement of parte illustrated.` in the accompanying drawing, and while we have shown therein a preferred embodiment, it is to be understood that the same is susceptible of modification and chanac, and comprehends other details, arrangements of parts, features and constructions without departing from the spirit of the invention.

In the drawing, the figure is a side view of our novel coifee roaster with parts broken away and with other parts in vertical cross section.

Referring more particularly to the disclosed embodiment, our invention comprises a roasting unit housed in cabinet I having opening and loading mechanism (not shown) on its top 2 for the green coiee container Il. The container has front 4, back 5 and bottom 8 and may be provided with casters 1.

Mounted suitably from plate 2 in the top of the cabinet is roasting chamber 8 covered with insulating material 9, and having agitator or impeller I0 in the bottom thereof rotatable on shaft II driven through suitable gearing in gear box I2, mounted in the lower part of cabinet I. The searing is driven by motor Il by means of worm I4 and wormgear I5.

Directly underneath the roasting chamber and communicating therewith through discharge door I 6 operated by solenoid I1 is the dry quenching or rst cooling chamber It of larger size than the roasting chamber and provided with impeller or agitator I9 also rotatable on shaft This chamber is preferably made of metal and is provided witli screened opening I8* in its lower rear side for the admission oi' air to the chamber. In the bottom oi this chamber il is a small discharge opening 2li through which a small quantity of roasted coil'ee will be pushed by every rotation of each blade of the impeller |9. This impeller is preferably three-bladed while the impeller il in the roasting chamber is preferably two-bladed. We do not conne ourselves however to impellers of any particular number of blades.

Directly beneath opening 2l is the second cooling chamber `2I comprising a screened or foraminous container or tray, reenforced by bands 22 and having handle 23 for permitting the operator to remove the tray from compartment 24 in iront of the cabinet. The container may also be provided with cone shaped member 2B mounted on wire or bar 28 extending from the sides of the container. This member is so positioned that when the container is in the compartment 24 it will be directly under opening 20 so that the coffee falling therethrough will contact it and be spread over the bottom oi' the container instead of forming a pile beneath the opening. The bands 22 are designed also to keep the container spaced from the side walls of the compartment to insure free circulation of air on all sides oi the u container.

l In the bottom o! the compartment 24 is opening 21 connecting with pipe or air passage 28 leading to blower 28 which may be a sirocco or other exhaust fan operated by belt 30 from motor I3. From the blower leads exhaust pipe 3| to a point of discharge outside the cabinet (not shown). The roaster may also be equipped with an aspirating device for the roasting and dry quenchn ing or nrst cooling chamber. This comprises cyassume lindrical housing or pipe 32 connected to annular chamber 33 in the top of the cabinet and having screened part 34 therein which comprises the coiee passage between the green coffee container '3 and roasting chamber 8. In the housing 32 is perforated or screened cylinder 35 forming a illter and adapted to register with opening $6 in port 34. The housing 32 is closed at its outer end by removable cap Il at the front of the cabinet.

The housing 32 is connected to exhaust pipe 2l which is bent so as to join exhaust pipe 3| at 39.. Pipe I8 is also connected at 40 to pipe 4| leading from opening 42 in the dry quenching or first cooling chamber IB and emptying into pipe 3l at 43.

The operation of our roaster is as follows: After thebatch of coffee in the roasting chamber 8 has attained the predetermined correct roasting temperature, a thermostat (not shown) causes the solenoid I'I to open the discharge door I6 in the roasting chamber and the coiee therein is expelled through the doorway into the rst cooling chamber I8 where it is thoroughly agitated and mixed by the blades I9. The cool air is admitted to this chamber through opening I8 which is preferably screened and circulation of air is kept up therein by means of the aspiratiug effect created by the blower 28 in the pipe 384| which draws air from opening I8 through the coiee and out opening 42. Small quantities of coffee are discharged from the rst chamber I8 to the second chamber 2| through the opening 20. As the coffee falls through this opening it contacts the stopl member and is scattered over the entire floor of the chamber 2| where it is subjected to the strong draft from the blower 29 through pipe 28. In a relatively short time the entire batch of coifee has been expelled from the chamber I8 into the chamber 2| where it may be removed as desired by the operator by means of pulling .the container 2| out of the cabinet by handle 23. The chamber I8 is then ready for another batch.

The operation of the blower 29 and agitator means I0 and I9 are continuous. By reason of this continuous operation of the pump, a strong suction means is always present in the roasting chamber 8 and the cooling chamber I8 by reason of the aspirating effect through pipes 38, 32 and 4|. All the moist chaff. dirt, etc. is therefore removed from these chambers without coming in contact with the blower means. The loose chai! and dirt, however, in chamber 2| will be relatively dry and may safely pass through the blower means.

Having thus disclosed our invention, we claim: l. The method of cooling and conditioning a batch of hot freshly roasted coiee beans which consists in vigorously stirring said batch of hot coffee beans in av dry quenching chamber and in the presence of moving cool air, positively forcing currents of cool air around and between the coffee beans and through and beyond the batch to arrest the roast, gradually discharging the coil'ee beans from said batch in small quantitles into a separate cooling chamber, and positively forcing cool air around and between the said gradually discharged coilee beans in said separate cooling chamber to a greater degree than that oi' the cool air forced through said batch in the dry quenching chamber.

2. The method of cooling and conditioning a batch of hot freshly roasted coiee beans in two stages, which consists in the first stage of vigormay 4stirring said batch or not @see beans in from the rst stage in small quantities into a..

separate cooling chamber and positively forcing cool air in strong currents around and between the coee beans in the separate cooling chamber and while being introduced thereinto to quickly cool the beans.

3. 'I'he method of cooling and conditioning a batch of hot freshly roasted coilee beans, which consists in vigorously stirring said batch in a dry quenching chamber having means for the entry oi air thereinto, positively forcing cool.

air around and between the coiee beans and through and beyond the batch to dry quench the batch and suddenly arrest the roast by dissipating the absorbed heat without rapid cooling so as to prevent over-roasting and scorching of the coffee beans or causing the oils in the bean to vaporize or the pores of the beans to close too rapidly and prevent the reentry of the oils into the beans and loss of flavor and aroma, gradually discharging the dry quenched coilee beans in small quantities into a toraminous cooling container. and positively forcing a large quantity of cool air through the cooling container whereby vaporlzation o! Athe oils is prevented by rapid cooling and to make room for another batch.

4. In apparatus for cooling and conditioning a batch of hot freshly roasted coffee beans, comprising a fiat bottom dry quenching chamber adapted to receive the hot roasted beans directly from a roaster, an impeller in said chamber,

the impeller having horizontally elongated blades the bottom edges of which blades for substantially their full length are approximately in contact with the nat bottom of the quenching chamber, means to rotate said impeller to rapidly and uniformly move the beans in circular gyratory paths throughout the chamber thereby separating, rolling, spinning and swirling the beans in various paths and in loose condition, a portion of said chamber being ioraminated to permit the entry oi cool air therethrough, means for creating currents of cool air through the chamber to quench but not too rapidly cool the coiee beans, the bottom of the chamber having a reltricted opening, a foraminous' cooling container below said opening in the quenching chamber, means in the cooling container for spreading the beans over' the container iloor as they are gradually discharged through said chamber opening, and means for causing a positive passage of cool air through the container and between and around the coffee beansV thermn, to

v prevent vaporization ot the oils of the coiiee beanswhich a batch of hot freshly roasted coilee beans is periodically discharged from the roasting chamber, a rotary stirring impeller inthe dry quenching chamber for vigorously stirring the coffee beans, means for rotating said impellcr, means in the quenching chamber walls for permittingthe entry of cool air therethrough, means for causing positive currents of cool air to pass into and through the quenching chamber and around and between the coiee beans there-v in to dry quench the coilee batch and arrest the roasting without too rapid drop of temperature, a cooling container, means 'for discharging the coiee beans from the quenching chamber to the cooling chamber, and means for causing a positive passage of cool air currents through the cooling container Vand around and between the coee beans therein to provide rapid cooling to prevent vaporization of theoils of the coffee beans and to make room for; another roasted batch.

6. In apparatus for cooling and conditioning a batch oi hot freshly roasted coffee beans, comprising a dry quenching chamber 'adapted to receive a batch of said hot coilee beans, means inl said quenching chamber for vigorously stirring the hot coijee beans therein, means in said quenching chamber for admitting cooling air thereinto, means for causing positive currents of cooling air to pass into and through said chamber and around and between the coffee beans therein to dry quench said hot coilee beans and arrest the roasting without too rapid drop of temperature,.a cooling container, means for discharging quenched coil'ee beans from vsairl quenching chamberinto the cooling container, and means for causing a positive passage of cooling air currents through the cooling container and around and between the coilee beans to rapidly cool the same, to prevent vaporization of oils and make room i'or another batch.

DONALD W. ADAMS. RICHARD L. SCHUHIANN. 

